U.S. patent application number 12/731780 was filed with the patent office on 2011-09-29 for defining approach maps for traffic signal preemption controllers.
Invention is credited to David John Edwardson.
Application Number | 20110234423 12/731780 |
Document ID | / |
Family ID | 44124280 |
Filed Date | 2011-09-29 |
United States Patent
Application |
20110234423 |
Kind Code |
A1 |
Edwardson; David John |
September 29, 2011 |
Defining Approach Maps for Traffic Signal Preemption
Controllers
Abstract
Methods and systems for creating an approach map for a traffic
signal preemption controller. A road map is displayed, and in
response to user input for instantiating a first segment of an
approach map, a first instance of a graphical object overlaying one
of the plurality of roads is displayed. The one road represents an
approach road to an intersection having the preemption controller.
First segment location data that describes a first geographical
area bounded by the first segment are determined from size and
placement of the first instance of the graphical object on the road
map and from location data associated with the one road. The first
segment location data are stored in association with the approach
map for the preemption controller. The preemption controller, once
configured with the first segment location data, initiates traffic
signal preemption in response to a preemption request transmitted
from within the first geographic area described by the first
segment location data.
Inventors: |
Edwardson; David John;
(Shoreview, MN) |
Family ID: |
44124280 |
Appl. No.: |
12/731780 |
Filed: |
March 25, 2010 |
Current U.S.
Class: |
340/906 |
Current CPC
Class: |
G08G 1/087 20130101 |
Class at
Publication: |
340/906 |
International
Class: |
G08G 1/07 20060101
G08G001/07 |
Claims
1. A method for creating an approach map for a traffic signal
preemption controller, comprising: displaying a road map with a
computer system, wherein the road map represents a plurality of
roads and intersections; displaying in response to user input for
instantiating a first segment of an approach map, a first instance
of a graphical object overlaying one of the plurality of roads, the
one road representing an approach road to an intersection having
the premption controller; determining first segment location data
descriptive of a first geographical area bounded by the first
segment from size and placement of the first instance of the
graphical object on the road map and from location data associated
with the one road; and storing in a processor-readable storage
device, the first segment location data in association with the
approach map for the preemption controller, wherein the preemption
controller, once configured with the first segment location data,
initiates traffic signal preemption in response to a preemption
request transmitted from within the first geographic area described
by the first segment location data.
2. The method of claim 1, further comprising: displaying in
response to user input for instantiating a second segment of the
approach map, a second instance of the graphical object overlaying
the one road; determining second segment location data descriptive
of a second geographical area bounded by the second segment from
size and placement of the second instance of the graphical object
on the road map and from location data associated with the one
road; and storing in the processor-readable storage device, the
second segment location data in association with the approach map
for the preemption controller, wherein the preemption controller,
once configured with the second segment location data, initiates
traffic signal preemption in response to a preemption request
transmitted from within the second geographic area described by the
second segment location data.
3. The method of claim 1, further comprising: displaying in
response to user input for instantiating a second segment of the
approach map, a second instance of the graphical object overlaying
a second one of the plurality of roads; determining second segment
location data descriptive of a second geographical area bounded by
the second segment from size and placement of the second instance
of the graphical object on the road map and from location data
associated with the second one of the roads; and storing in the
processor-readable storage device, the second segment location data
in association with the approach map for the preemption controller,
wherein the preemption controller, once configured with the second
segment location data, initiates traffic signal preemption in
response to a preemption request transmitted from within the second
geographic area described by the second segment location data.
4. The method of claim 2, further comprising: providing
user-controllable linking handles on each of the first and second
instances of the graphical objects; attaching the first instance to
the second instance of the graphical object via the linking handles
in response to coincident placement of the linking handles by the
user; and in response to movement of the first instance of the
graphical object by a user after the attaching, moving the second
instance of the graphical object by an amount and in a direction
equal to movement of the first instance of the graphical
object.
5. The method of claim 3, further comprising: providing
user-controllable linking handles on each of the first and second
instances of the graphical objects; and attaching the first
instance to the second instance of the graphical object via the
linking handles in response to coincident placement of the linking
handles by the user.
6. The method of claim 1, further comprising: providing
user-controllable sizing handles on the first instance of the
graphical object; and adjusting size of the first instance of the
graphical object in response to user movement of one of the sizing
handles.
7. The method of claim 1, further comprising displaying
user-editable textual data describing the first segment, wherein
the user-editable textual data specifies changes in X and Y
coordinates from an intersection to a geographic location
represented by an endpoint of the first instance of the graphical
object.
8. The method of claim 1, further comprising displaying
user-editable textual data describing the first segment, wherein
the user-editable textual data specifies changes in width of the
first geographical area.
9. The method of claim 1, further comprising: storing a plurality
of geography points in a processor-readable storage device, each
geography point describing a geographic location on one or more new
roads having no representation in the road map; displaying on the
road map, a plurality of point-type objects corresponding to the
plurality of geography points, respectively; displaying in response
to user input for instantiating a second segment of an approach
map, a second instance of a graphical object overlaying a subset of
the point-type objects corresponding to one of the one or more new
roads, the one new road representing an approach road to an
intersection having a premption controller; determining second
segment location data descriptive of a second geographical area
bounded by the second segment from size and placement of the second
instance of the graphical object on the road map and from the
respective geography points corresponding to the subset of the
point-type objects; and storing in a processor-readable storage
device, the second segment location data in association with an
approach map for a preemption controller, wherein the preemption
controller, once configured with the second segment location data,
initiates traffic signal preemption in response to a preemption
request transmitted from within the second geographic area
described by the second segment location data.
10. A system for managing geographically dispersed traffic signal
preemption control equipment, the traffic signal preemption control
equipment including traffic signal preemption controllers and
vehicle control units, comprising: at least one processor; a memory
arrangement coupled to the processor, wherein the memory
arrangement is configured with instructions for execution by the
processor, wherein execution of the instructions by the at least
one processor causes the at least one processor to perform the
operations including: displaying a road map, wherein the road map
represents a plurality of roads and intersections; displaying in
response to user input for instantiating a first segment of an
approach map, a first instance of a graphical object overlaying one
of the plurality of roads, the one road representing an approach
road to an intersection having the premption controller;
determining first segment location data descriptive of a first
geographical area bounded by the first segment from size and
placement of the first instance of the graphical object on the road
map and from location data associated with the one road; and
storing the first segment location data in association with the
approach map for the preemption controller, wherein the preemption
controller, once configured with the first segment location data,
initiates traffic signal preemption in response to a preemption
request transmitted from within the first geographic area described
by the first segment location data.
11. The system of claim 10, further comprising: displaying in
response to user input for instantiating a second segment of the
approach map, a second instance of the graphical object overlaying
the one road; determining second segment location data descriptive
of a second geographical area bounded by the second segment from
size and placement of the second instance of the graphical object
on the road map and from location data associated with the one
road; and storing in the processor-readable storage device, the
second segment location data in association with the approach map
for the preemption controller, wherein the preemption controller,
once configured with the second segment location data, initiates
traffic signal preemption in response to a preemption request
transmitted from within the second geographic area described by the
second segment location data.
12. The system of claim 10, further comprising: displaying in
response to user input for instantiating a second segment of the
approach map, a second instance of the graphical object overlaying
a second one of the plurality of roads; determining second segment
location data descriptive of a second geographical area bounded by
the second segment from size and placement of the second instance
of the graphical object on the road map and from location data
associated with the second one of the roads; and storing in the
processor-readable storage device, the second segment location data
in association with the approach map for the preemption controller,
wherein the preemption controller, once configured with the second
segment location data, initiates traffic signal preemption in
response to a preemption request transmitted from within the second
geographic area described by the second segment location data.
13. The system of claim 11, further comprising: providing
user-controllable linking handles on each of the first and second
instances of the graphical objects; attaching the first instance to
the second instance of the graphical object via the linking handles
in response to coincident placement of the linking handles by the
user; and in response to movement of the first instance of the
graphical object by a user after the attaching, moving the second
instance of the graphical object by an amount and in a direction
equal to movement of the first instance of the graphical
object.
14. The system of claim 12, further comprising: providing
user-controllable linking handles on each of the first and second
instances of the graphical objects; and attaching the first
instance to the second instance of the graphical object via the
linking handles in response to coincident placement of the linking
handles by the user.
15. The system of claim 10, further comprising: providing
user-controllable sizing handles on the first instance of the
graphical object; and adjusting the size of the first instance of
the graphical object in response to user movement of one of the
sizing handles.
16. The system of claim 10, further comprising displaying
user-editable textual data describing the first segment, wherein
the user-editable textual data specifies changes in X and Y
coordinates from an intersection to a geographic location
represented by an endpoint of the first instance of the graphical
object.
17. The system of claim 10, further comprising displaying
user-editable textual data describing the first segment, wherein
the user-editable textual data specifies changes a width of the
first geographical area.
18. The system of claim 10, further comprising: storing a plurality
of geography points in a processor-readable storage device, each
geography point describing a geographic location on one or more new
roads having no representation in the road map; displaying on the
road map, a plurality of point-type objects corresponding to the
plurality of geography points, respectively; displaying in response
to user input for instantiating a second segment of an approach
map, a second instance of a graphical object overlaying a subset of
the point-type objects corresponding to one of the one or more new
roads, the one new road representing an approach road to an
intersection having a premption controller; determining second
segment location data descriptive of a second geographical area
bounded by the second segment from size and placement of the second
instance of the graphical object on the road map and from the
respective geography points corresponding to the subset of the
point-type objects; and storing in a processor-readable storage
device, the second segment location data in association with an
approach map for a preemption controller, wherein the preemption
controller, once configured with the second segment location data,
initiates traffic signal preemption in response to a preemption
request transmitted from within the second geographic area
described by the second segment location data.
19. An article of manufacture, comprising: a processor-readable
storage device configured with instructions for managing
geographically dispersed traffic signal preemption control
equipment, the traffic signal preemption control equipment
including traffic signal preemption controllers and vehicle control
units, wherein in executing the instructions by one or more
processors causes the one or more processors to perform the
operations including: displaying a road map, wherein the road map
represents a plurality of roads and intersections; displaying in
response to user input for instantiating a first segment of an
approach map, a first instance of a graphical object overlaying one
of the plurality of roads, the one road representing an approach
road to an intersection having the premption controller;
determining first segment location data descriptive of a first
geographical area bounded by the first segment from size and
placement of the first instance of the graphical object on the road
map and from location data associated with the one road; and
storing in a processor-readable storage device, the first segment
location data in association with the approach map for the
preemption controller, wherein the preemption controller, once
configured with the first segment location data, initiates traffic
signal preemption in response to a preemption request transmitted
from within the first geographic area described by the first
segment location data.
Description
FIELD OF THE INVENTION
[0001] The present invention is generally directed to traffic
control preemption systems.
BACKGROUND
[0002] Traffic signals have long been used to regulate the flow of
traffic at intersections. Generally, traffic signals have relied on
timers or vehicle sensors to determine when to change traffic
signal lights, thereby signaling alternating directions of traffic
to stop, and others to proceed.
[0003] Emergency vehicles, such as police cars, fire trucks and
ambulances, generally have the right to cross an intersection
against a traffic signal. Emergency vehicles have in the past
typically depended on horns, sirens and flashing lights to alert
other drivers approaching the intersection that an emergency
vehicle intends to cross the intersection. However, due to hearing
impairment, air conditioning, audio systems and other distractions,
often the driver of a vehicle approaching an intersection will not
be aware of a warning being emitted by an approaching emergency
vehicle.
[0004] Traffic control preemption systems assist authorized
vehicles (police, fire and other public safety or transit vehicles)
through signalized intersections by making a preemption request to
the intersection controller. The controller will respond to the
request from the vehicle by changing the intersection lights to
green in the direction of the approaching vehicle. This system
improves the response time of public safety personnel, while
reducing dangerous situations at intersections when an emergency
vehicle is trying to cross on a red light. In addition, speed and
schedule efficiency can be improved for transit vehicles.
[0005] There are presently a number of known traffic control
preemption systems that have equipment installed at certain traffic
signals and on authorized vehicles. One such system in use today is
the OPTICOM.RTM. system. This system utilizes a high power strobe
tube (emitter), located in or on the vehicle, that generates light
pulses at a predetermined rate, typically 10 Hz or 14 Hz. A
receiver, which includes a photo detector and associated
electronics, is typically mounted on the mast arm located at the
intersection and produces a series of voltage pulses, the number of
which are proportional to the intensity of light pulses received
from the emitter. The emitter generates sufficient radiant power to
be detected from over 2500 feet away. The conventional strobe tube
emitter generates broad spectrum light. However, an optical filter
is used on the detector to restrict its sensitivity to light only
in the near infrared (IR) spectrum. This minimizes interference
from other sources of light.
[0006] Intensity levels are associated with each intersection
approach to determine when a detected vehicle is within range of
the intersection. Vehicles with valid security codes and a
sufficient intensity level are reviewed with other detected
vehicles to determine the highest priority vehicle. Vehicles of
equivalent priority are selected in a first come, first served
manner. A preemption request is issued to the controller for the
approach direction with the highest priority vehicle travelling on
it.
[0007] Another common system in use today is the OPTICOM.RTM. GPS
priority control system. This system utilizes a GPS receiver in the
vehicle to determine location, speed, and heading of the vehicle.
The information is combined with security coding information that
consists of an agency identifier, vehicle class, and vehicle ID and
is broadcast via a proprietary 2.4 GHz radio.
[0008] An equivalent 2.4 GHz radio located at the intersection
along with associated electronics receives the broadcasted vehicle
information. Approaches to the intersection are mapped using either
collected GPS readings from a vehicle traversing the approaches or
using location information taken from a map database. The vehicle
location and direction are used to determine on which of the mapped
approaches the vehicle is approaching toward the intersection and
the relative proximity to it. The speed and location of the vehicle
are used to determine the estimated time of arrival (ETA) at the
intersection and the travel distance from the intersection. ETA and
travel distances are associated with each intersection approach to
determine when a detected vehicle is within range of the
intersection and, therefore, a preemption candidate. Preemption
candidates with valid security codes are reviewed with other
detected vehicles to determine the highest priority vehicle.
Vehicles of equivalent priority are generally selected in a first
come, first served manner. A preemption request is issued to the
controller for the approach direction with the highest priority
vehicle travelling on it.
[0009] With metropolitan-wide networks becoming more prevalent,
additional means for detecting vehicles via wired networks such as
Ethernet or fiber optics and wireless networks such as Mesh or IEEE
802.11b/g may be available. With network connectivity to the
intersection, vehicle tracking information may be delivered over a
network medium. In this instance, the vehicle location is either
broadcast by the vehicle itself over the network or it may
broadcast by an intermediary gateway on the network that bridges
between, for example, a wireless medium used by the vehicle and a
wired network on which the intersection electronics resides. In
this case, the vehicle or an intermediary reports, via the network,
the vehicle's security information, location, speed, and heading,
along with the current time. Intersections on the network receive
the vehicle information and evaluate the position using approach
maps as described in the OPTICOM.RTM. GPS system. The security
coding could be identical to the OPTICOM.RTM. GPS system or employ
another coding scheme.
[0010] As used herein, the term "vehicle control unit" refers to
the various types of modules capable of communicating a preemption
request to a preemption controller. This includes, for example, IR
light based modules, GPS based modules, and wireless network based
modules. In addition, a preemption request refers to both
preemption requests that emanate from emergency vehicles and to
what are sometimes referred to as "priority requests," which
emanate from mass transit vehicles, for example.
SUMMARY
[0011] The embodiments of the invention provide methods and systems
for creating an approach map for a traffic signal preemption
controller. In one embodiment, a method includes displaying a road
map with a computer system. The road map represents a plurality of
roads and intersections. In response to user input for
instantiating a first segment of an approach map, a first instance
of a graphical object overlaying one of the plurality of roads is
displayed. The one road represents an approach road to an
intersection having the premption controller. First segment
location data descriptive of a first geographical area bounded by
the first segment are determined from size and placement of the
first instance of the graphical object on the road map and from
location data associated with the one road. The first segment
location data are stored in association with the approach map for
the preemption controller in a processor-readable storage device.
The preemption controller, once configured with the first segment
location data, initiates traffic signal preemption in response to a
preemption request transmitted from within the first geographic
area described by the first segment location data.
[0012] In another embodiment, a system is provided for managing
geographically dispersed traffic signal preemption control
equipment. The traffic signal preemption control equipment includes
traffic signal preemption controllers and vehicle control units.
The system includes at least one processor and a memory arrangement
coupled to the processor. The memory arrangement is configured with
instructions for execution by the processor. Execution of the
instructions by the at least one processor causes the at least one
processor to display a road map. The road map represents a
plurality of roads and intersections. In response to user input for
instantiating a first segment of an approach map, a first instance
of a graphical object overlaying one of the plurality of roads is
displayed. The one road represents an approach road to an
intersection having the premption controller. First segment
location data descriptive of a first geographical area bounded by
the first segment are determined from size and placement of the
first instance of the graphical object on the road map and from
location data associated with the one road. The first segment
location data are stored in association with the approach map for
the preemption controller. The preemption controller, once
configured with the first segment location data, initiates traffic
signal preemption in response to a preemption request transmitted
from within the first geographic area described by the first
segment location data.
[0013] Another embodiment is an article of manufacture that
includes a processor-readable storage device configured with
instructions for managing geographically dispersed traffic signal
preemption control equipment. The traffic signal preemption control
equipment includes traffic signal preemption controllers and
vehicle control units. Executing the instructions by one or more
processors causes the one or more processors to perform operations
including displaying a road map. The road map represents a
plurality of roads and intersections. The operations further
include displaying in response to user input for instantiating a
first segment of an approach map, a first instance of a graphical
object overlaying one of the plurality of roads. The one road
represents an approach road to an intersection having the premption
controller. First segment location data descriptive of a first
geographical area bounded by the first segment are determined from
size and placement of the first instance of the graphical object on
the road map and from location data associated with the one road.
The operations also include storing the first segment location data
in association with the approach map for the preemption controller.
The preemption controller, once configured with the first segment
location data, initiates traffic signal preemption in response to a
preemption request transmitted from within the first geographic
area described by the first segment location data.
[0014] The above summary of the present invention is not intended
to describe each disclosed embodiment of the present invention. The
figures and detailed description that follow provide additional
example embodiments and aspects of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Various aspects and advantages of the invention will become
apparent upon review of the following detailed description and upon
reference to the drawings in which:
[0016] FIG. 1 is an illustration of a typical intersection having
traffic signal lights;
[0017] FIG. 2 is a block diagram of an example system for defining
approach maps for traffic signal preemption controllers in
accordance with an embodiment of the invention;
[0018] FIG. 3 is a flowchart of an example process for creating
approach maps in accordance with one or more embodiments of the
invention;
[0019] FIG. 4 shows an example display screen in which a road map
is displayed in combination with different approach maps for
preemption controllers at different intersections;
[0020] FIG. 5 shows an example display screen for displaying and/or
editing various attributes of individual segments of an approach
map;
[0021] FIG. 6 is a flowchart of an example process for creating an
approach map in accordance with another embodiment of the
invention;
[0022] FIG. 7 shows an example display screen in which the road map
is out-of-date and does not show a new road; and
[0023] FIG. 8 is a block diagram of an example computing
arrangement which can be configured to implement the processes
performed by the preemption controller and central systems server
described herein.
DETAILED DESCRIPTION
[0024] Some traffic signal preemption systems, such as GPS-based
systems, use approach maps in determining when to preempt a traffic
signal. Generally, an approach map defines the boundaries of an
area relative to a preemption controller. If an authorized vehicle
is within the defined boundaries and communicates a preemption
request to the preemption controller, the preemption is granted,
assuming there is no competing, higher-priority request.
[0025] Prior systems for creating approach maps required personnel
to travel on the road for which the approach is desired and record
GPS waypoints while moving. The gathered waypoints were then used
to define the boundaries of an approach map. Once the boundaries
were defined, a traffic engineer would connect a programming device
to the preemption controller and program the controller with the
approach map. Such a process may be time consuming and expensive
since travel was required on every road of every intersection where
an approach map was desired.
[0026] The various embodiments of the invention provide methods and
systems for creating approach maps for a traffic signal preemption
controller without requiring travel to the intersections. In one
embodiment, a road map is displayed with a computer system. The
road map represents a plurality of roads and intersections. In
response to user input for instantiating a first segment of an
approach map, a first instance of a graphical object is displayed
overlaid on one of the roads in the road map. The road represents
an approach to an intersection having a premption controller of
interest. From size and placement of the first instance of the
graphical object on the road map and from location data associated
with the road, the method determines location data that describes a
first geographical area represented by the first segment. The first
segment location data are stored in a processor-readable storage
device in association with the approach map for the preemption
controller. The preemption controller, once configured with the
first segment location data, initiates traffic signal preemption in
response to a preemption request transmitted from within the first
geographic area described by the first segment location data.
[0027] FIG. 1 is an illustration of a typical intersection 10
having traffic signal lights 12. The equipment at the intersection
illustrates the environment in which embodiments of the present
invention may be used. A traffic signal controller 14 sequences the
traffic signal lights 12 to allow traffic to proceed alternately
through the intersection 10. The intersection 10 may be equipped
with a traffic control preemption system such as the OPTICOM.RTM.
Priority Control System, the OPTICOM GPS priority control system,
or a networked system.
[0028] The traffic control preemption system shown in FIG. 1
includes detector assemblies 16A and 16B, signal emitters 24A, 24B
and 24C (also referred to herein as "vehicle control units"), a
traffic signal controller 14, and a phase selector 18 (also
referred to herein as a "preemption controller"). The detector
assemblies 16A and 16B are stationed to detect signals emitted by
authorized vehicles approaching the intersection 10. The detector
assemblies 16A and 16B communicate with the phase selector, which
is typically located in the same cabinet as the traffic controller
14.
[0029] In FIG. 1, an ambulance 20 and a bus 22 are approaching the
intersection 10. The signal emitter 24A is mounted on the ambulance
20 and the signal emitter 24B is mounted on the bus 22. The signal
emitters 24A and 24B each transmit a signal that is received by
detector assemblies 16A and 16B. The detector assemblies 16A and
16B send output signals to the phase selector. The phase selector
processes the output signals from the detector assemblies 16A and
16B to determine the signal characteristics including: frequency,
intensity, and security code of the signal waveform, or pulses. The
security code, consisting of the vehicle class and vehicle
identification is encoded in the signal by interleaving data pulses
between the base frequency pulses. In GPS systems, location, speed,
and heading of the vehicle are also determined and transmitted to
the phase selector. The phase selector in a GPS system uses the
location data to determine whether or not the vehicle is within the
boundaries or an approach map. If so, the preemption request may be
granted. In optical systems, if an acceptable frequency, intensity,
and or security code is observed the phase selector generates a
preemption request to the traffic signal controller 14 to preempt a
normal traffic signal sequence. The phase selector alternately
issues preemption requests to and withdraws preemption requests
from the traffic signal controller, and the traffic signal
controller determines whether the preemption requests can be
granted. The traffic signal controller may also receive preemption
requests originating from other sources, such as a nearby railroad
crossing, in which case the traffic signal controller may determine
that the preemption request from the other source be granted before
the preemption request from the phase selector. In some embodiments
of the present invention the function of the phase selector is
performed solely by the traffic controller.
[0030] The traffic controller determines the priority of each
signal received and whether to preempt traffic control based on the
security code contained in the signal. For example, the ambulance
20 may be given priority over the bus 22 since a human life may be
at stake. Accordingly, the ambulance 20 would transmit a preemption
request with a security code indicative of a high priority while
the bus 20 would transmit a preemption request with a security code
indicative of a low priority. The phase selector would discriminate
between the low and high priority signals and request the traffic
signal controller 14 to cause the traffic signal lights 12
controlling the ambulance's approach to the intersection to remain
or become green and the traffic signal lights 12 controlling the
bus's approach to the intersection to remain or become red.
[0031] FIG. 2 is a block diagram of an example system for defining
approach maps for traffic signal preemption controllers in
accordance with an embodiment of the invention. Traffic lights 202
and 204 at intersections with preemption controllers are coupled to
traffic signal controllers 210 and 214, respectively. Traffic
signal controllers 210 and 214 are connected to respective
preemption controllers 216 and 218. Each preemption controller is
configured with memory for storing approach maps (not shown). A
management system 220 and the preemption controllers are
respectively coupled to network adapters 220, 224, and 226 for
communication over a network 228. In various embodiments, a router
or a network switch, as shown by router 230, may be coupled between
the network adapter and the network. It is understood the
management system 220 and the preemption controllers 216 and 218
may be connected through more than one network, coupled by
additional switches and routing resources, including a connection
over the Internet.
[0032] The management system 220 is additionally coupled to a
storage arrangement 232, which stores approach maps 234, along with
road maps and associated location data 236. Each approach map is
associated with one of the preemption controllers 216 or 218 and
includes data that define the boundaries of a geographic area near
a road that approaches the preemption controller. The
boundary-defining data of an approach map is derived from the
placement of the approach map relative to a road on the display
device 238, in combination with the location data describing the
road. It will be recognized that storage arrangement 232 may
comprise several local and/or remote servers and one or more
databases.
[0033] The management system 220 provides a system for creating the
approach maps and configuring the preemption controllers with the
approach maps. The interface allows a user to create, edit, and
delete approach maps. In response to user selection of a geographic
area, the management system displays the road map on a computer
monitor, for example. In one embodiment, data from a geographic
information system (GIS) is used in preparing and displaying the
road map. The GIS includes GPS data associated with locations on
the road map. The management system provides an interface for
instantiating approach maps on the road map as displayed on the
display device. The relative placement of an approach map on the
displayed road map and the GPS data associated with the road map
are used to determine the boundaries of the approach map. The
approach map is downloaded to the proper preemption controller.
Stored approach maps 234 may similarly be edited or deleted with
the management system, and updated configurations downloaded to the
proper preemption controllers 216 and 218.
[0034] It is understood that numerous network transfer protocols
may be used to establish, maintain, and route connections
including: TCP/IP, UDP, NFS, ESP, SPX, etc. It is also understood
that network transfer protocols may utilize one or more lower
layers of protocol communication such as ATM, X.25, or MTP, and on
various physical and wireless networks such as, Ethernet, ISDN,
ADSL, SONET, IEEE 802.11, V.90/v92 analog transmission, etc.
[0035] FIG. 3 is a flowchart of an example process for creating
approach maps in accordance with one or more embodiments of the
invention. A road map is displayed on a computer display device at
step 302. The display of the map may be initiated by a user
operating a user interface and designating a locale for which the
roads are to be displayed. As indicated above, the map information
may be provided by a GIS.
[0036] At step 304, in response to user input, one or more objects
are instantiated and displayed on the road map. Each object
represents a segment of an approach map. In one embodiment, each
object may be moved by selecting the object and dragging the object
with a mouse. Similarly, the size of the segment may be adjusted by
dragging handles on the object. An approach map may include one or
more segments. Multiple segments may be grouped or linked into one
approach map.
[0037] The geographic boundaries of the segment represented by the
object are determined at step 306 using the placement of the object
relative to the displayed road in combination with the geographic
location data, e.g., GPS data, associated with road. At step 308,
the geographic location data of the segment are stored in
association with an approach map for a particular preemption
controller. The process may then be repeated for other approaches
to the intersection as shown by the step 310 that returns the
process to step 304.
[0038] At step 312, the preemption controller is configured with
one or more approach maps. Generally, each approach to an
intersection has an approach map. The preemption controller, once
configured with location data of an approach map, initiates traffic
signal preemption in response to a preemption request transmitted
from within the boundaries of the approach map. At step 314, the
process may be returned to step 304 to create approach maps for
other preemption controllers.
[0039] FIG. 4 shows an example display screen in which a road map
is displayed in combination with different approach maps for
preemption controllers at different intersections. FIG. 4 shows
three different approach maps for three different preemption
controllers 402, 404, and 406 at three different intersections.
Depending on implementation and user requirements, the display may
be limited to displaying the approach maps for one intersection at
a time. Alternatively, the approach maps of multiple intersections
may be displayed at one time.
[0040] In one embodiment, an approach map is created in response to
a user right-clicking on the map where the approach should be, and
selecting New/Approach from a pop-up menu (not shown). More
segments may be added to the approach by right-clicking a location
on the map and selecting New\Segment. A new segment can also be
added to the approach via the property grid control 450 on the
right-hand side of the map.
[0041] Each segment includes handles that can be manipulated for
resizing the segment. For example, segment 408 has handles 410,
412, 414, and 416. Clicking and dragging a handle with a mouse
expands or contracts the segment depending on the direction in
which the handle is moved. The entire segment can be moved by
selecting the segment and dragging it with a mouse, for
example.
[0042] This will also cause any attached segments to be adjusted.
The endpoint of a segment can be selected to adjust the length of
the segment and a selection handle will exist on the sides of the
selected segment to allow the segment width to be adjusted. Segment
408 shows an example of an approach map that includes only one
segment.
[0043] Approach maps may include any number of segments on any
number of roads. For example, the approach map for the preemption
controller associated with traffic signal 404 includes segments 420
and 422. The handles on the segments can be manipulated to attach
one segment to another. Once attached, the segments can be moved as
a single unit. For example, handle 424 shows alignment of handles
from both of segments 420 and 422. When so aligned, the system
recognizes the segments as being attached, and clicking on either
of the segments with a mouse and moving the mouse causes movement
of both segments. When two segments are attached each can be
individually resized.
[0044] A third example approach map is shown for the intersection
having traffic signal 406. The approach map includes segments 430,
432, 434, 436, and 438, all on one road. The segments are attached
via their coincident handles as shown.
[0045] In one embodiment, moving a cursor over a segment causes the
system to display data about the approach (name and preemption
controller channel) and the segment (width and length).
[0046] In another embodiment, a properties section on the right
side of the map displays properties of the selected approach. The
user may change the properties of the approach by modifying the
values (not shown) of the items in the properties section. The
properties section includes an identification subsection 440, a
components subsection 450, and a size subsection 460. The
Identification subsection includes the channel and name of the
approach map. The Components subsection includes a count of the
segments that define the approach. The segments in the approach can
be edited by clicking on the count of the segments and using a
popup editor to modify (e.g., length and/or width) of the
individual segments (see FIG. 5). The Size subsection includes the
overall length of the approach in meters and/or feet. The length is
the sum of the lengths of the segments.
[0047] FIG. 5 shows an example display screen for displaying and/or
editing various attributes of individual segments of an approach
map. The Map Points are the endpoints of the individual segments of
the approach. Each segment has two endpoints with the tail endpoint
of one segment being shared with the front endpoint of the next
segment. There are five map points for the four segments of the
example approach. In FIG. 5, Map Point [1] is selected for editing
as exemplified by box 502. The data in box 504 describe location of
the selected endpoint. These values can be edited by clicking on
the value and entering the desired value. The DX and DY values
represent the difference in X and Y coordinates from the
intersection preemption controller to the Map Point of the segment.
In one embodiment, only the width can be edited by entering the
displayed value, and editing of the length of a segment is limited
to dragging the handles of the corresponding object in the
interface shown in FIG. 4. In an alternative embodiment, any of the
values may be edited in the table of FIG. 5.
[0048] The Size values include the length and width of the segment
indicated by the selected Map Point. The length and width are also
user editable.
[0049] FIG. 6 is a flowchart of an example process for creating an
approach map in accordance with another embodiment of the
invention. The embodiment of FIG. 6 provides a method for creating
an approach map for a preemption controller in a situation where
the GIS does not yet have mapping data for one or more roads. For
example, when new roads are constructed in an area under
development it may be some time before the GIS has the necessary
data to display these roads.
[0050] According to the method of FIG. 6, at step 602 a vehicle
control unit is activated for initiating a preemption request while
moving along the desired approach. The preemption controller of
interest stores the GPS data associated with the preemption request
in its local memory at step 604. The approach management system
reads the stored GPS data from the preemption controller at step
606, and at step 608 a plot of the retrieved GPS data is displayed
for the user. In one embodiment, if there is any existing GIS data
available for the general vicinity of the GPS data, those roads may
be displayed in combination with the GPS plot.
[0051] At step 610, in response to user input, one or more objects
are instantiated and displayed along with the GPS plot. Each object
represents a segment of an approach map, and the segments may be
resized, placed, and oriented as described above. Once placed, at
step 612 the geographic boundaries of the segments represented by
the objects are determined using the placement of the objects
relative to the displayed GPS plot along with the associated GPS
data. At step 614, the geographic location data of the segment are
stored in association with an approach map for the desired
preemption controller. The process may then be repeated for other
approaches to the intersection. At step 616, the preemption
controller is configured with one or more approach maps.
[0052] FIG. 7 shows an example display screen in which the road map
is out-of-date and does not show a new road. The location data for
the new road, such as a new overpass, for example, is gathered by
transmitting location data of a vehicle as it traverses the new
road to a preemption controller associated with traffic signal 704.
The management system 220 reads the recorded GPS data from the
preemption controller, and that data can then be used to create
approach maps.
[0053] In response to user input that requests displaying the GPS
data gathered by a preemption controller, the management system
displays a plot of the GPS data. In the example, dots 706 represent
GPS data gathered by the preemption controller associated with
traffic signal 704. Each dot represents a GPS point transmitted to
the preemption controller from the vehicle. Once the plot of
location data is displayed, the user can create a segment as
described above. Instead of placing a segment relative to a road on
the map, the segment 708 may be sized, oriented, and placed
relative to the GPS plot. Each segment thus placed can be edited as
described above.
[0054] FIG. 8 is a block diagram of an example computing
arrangement which can be configured to implement the processes
performed by the preemption controller and central systems server
described herein. Those skilled in the art will appreciate that
various alternative computing arrangements, including one or more
processors and a memory arrangement configured with program code,
would be suitable for hosting the processes and data structures and
implementing the algorithms of the different embodiments of the
present invention. The computer code, comprising the processes of
the present invention encoded in a processor executable format, may
be stored and provided via a variety of computer-readable storage
media or delivery channels such as magnetic or optical disks or
tapes, electronic storage devices, or as application services over
a network.
[0055] Processor computing arrangement 800 includes one or more
processors 802, a clock signal generator 804, a memory unit 806, a
storage unit 808, a network adapter 814, and an input/output
control unit 810 coupled to host bus 812. The arrangement 800 may
be implemented with separate components on a circuit board or may
be implemented internally within an integrated circuit.
[0056] The architecture of the computing arrangement depends on
implementation requirements as would be recognized by those skilled
in the art. The processor 802 may be one or more general purpose
processors, or a combination of one or more general purpose
processors and suitable co-processors, or one or more specialized
processors (e.g., RISC, CISC, pipelined, etc.).
[0057] The memory arrangement 806 typically includes multiple
levels of cache memory and a main memory. The storage arrangement
808 may include local and/or remote persistent storage such as
provided by magnetic disks (not shown), flash, EPROM, or other
non-volatile data storage. The storage unit may be read or
read/write capable. Further, the memory 806 and storage 808 may be
combined in a single arrangement.
[0058] The processor arrangement 802 executes the software in
storage 808 and/or memory 806 arrangements, reads data from and
stores data to the storage 808 and/or memory 806 arrangements, and
communicates with external devices through the input/output control
arrangement 810 and network adapter 814. These functions are
synchronized by the clock signal generator 804. The resources of
the computing arrangement may be managed by either an operating
system (not shown), or a hardware control unit (not shown).
[0059] The present invention is thought to be applicable to a
variety of systems for a preemption controller. Other aspects and
embodiments of the present invention will be apparent to those
skilled in the art from consideration of the specification and
practice of the invention disclosed herein. It is intended that the
specification and illustrated embodiments be considered as examples
only, with a true scope and spirit of the invention being indicated
by the following claims.
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